网络通信是把许多的____ 联在一起进行通信，最经常使用的网络通信形式是____ ．

生态农业是能获得较高的经济效益、生态效益和社会效益的新型现代化农业．图是滨城区某一生态农场模式图．请据图回答：

   Time spent in a bookshop can be enjoyable. If you go to a 1shop, no assistant will come near to you and say “Can I help you? ” You 2buy anything you don’t want. You may try to 3where the book you want is. But if you can’t , the assistant will lead (引导 ) you there and then he will go away. It seems that he is4selling any books at all.
   Once a medical student found a very useful book in the shop, 5it was too expensive for him to buy. He couldn’t get it from the library, 6. So every afternoon, he went there to read7at a time. One day, however, he couldn’t find the book from its usual place and 8when he saw an assistant signing to him. To his surprise, the assistant pointed to the book in the corner, “I put 9 there so as not to be sold out,” said the assistant. Then he 10 the student to go on with his reading.